euler_p2.py

# Euler - problem 2
""" Each new term in the Fibonacci sequence is generated by adding the previous two terms.
By starting with 1 and 2, the first 10 terms will be: 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
By considering the terms in the Fibonacci sequence whose values do not exceed four million,
find the sum of the even-valued terms."""

(n1, n2) = (1, 2)
total = n2
small = True
while small:
    (n1, n2) = (n1 + 2*n2, 2*n1 + 3*n2) #IDEA: every third term in the sequence is even-valued
    if n2 <= 4e6: total += n2
    else: small = False

print total